Final answer:
The first known Mesoamerican civilization is the Olmec civilization, which flourished in the south-central regions of Mexico from 1200 B.C.E. to about 400 B.C.E.
Step-by-step explanation:
The first known Mesoamerican civilization is the Olmec civilization. The Olmec flourished in the south-central regions of Mexico from 1200 B.C.E. to about 400 B.C.E. They are considered the forerunners of all Mesoamerican cultures including the Maya and Aztecs. The Olmec are known for their intricate jade figurines and are regarded as the cultural hearth of the Mesoamerica region.